Japanese Patent Application Laid-Open No. 2005-328496 and Japanese Patent Application Laid-Open No. H09-068640 disclose prior art control systems for movable optical members related to zooming and focusing etc. in a television camera lens.
In these systems, a zoom demand serving as a command unit that outputs a command signal for zooming drive and a focus demand serving as a command unit that outputs a command signal for focusing drive are connected to a lens body.
A plurality of command units including a unit that outputs a stop command and a unit for controlling an image stabilizing optical system etc. can also be connected to the lens body in addition to the above-mentioned units.
Connection between the lens body and the command unit is established by cable connection using a connector. The connector disclosed in Japanese Patent Application Laid-Open No. 2005-328496 has a 20-pin configuration, and the cable used between the lens body and the command unit includes twenty (which is the same as the number of the pins of the connector) wires.
As disclosed in Japanese Patent Application Laid-Open No. H09-068640, the cable that is commonly prepared for use between the lens body and the command unit generally has a length of about 1 meter to allow operation of the command unit in the neighborhood of the lens body.
In shooting in a studio or the like, the television camera, television camera lens, zoom demand and focus demand are operated in a state in which they are mounted on tripods. Such an operation style will be referred to as tripod operation.
Alternatively, the television camera with the television lens combined thereto is shouldered by a camera operator without use of the zoom demand and the focus demand. Such an operation style will be referred to as shoulder operation.
FIG. 14 is a block diagram of a television shooting system according to the above mentioned prior art. A zoom demand 3 for operating the zoom lens of the lens body 2 mounted on the camera body 1 can output a return-switch command, a VTR-switch command, a shot command and a shot memory command in addition to a zoom command for controlling zoom drive.
A focus demand 4 for operating the focusing lens of the lens body 2 can output switch commands similar to those of the zoom demand 3 in addition to a focus command for controlling focus drive.
A commonly prepared cable 5, 6 including about twenty wires and having a length of about 1 meter and a connector 7, 8 are used to connect the lens body 1 and the zoom demand 3 or the focus demand 4.
In the above described prior art system, the lens body 2 and each demand 3, 4 are connected by a multi-conductor cable 5, 6, and if a plurality of command units or demands are to be connected to the lens body 2, the same number of cables as the number of the command units are required.
There are some shooting situations in which a camera with a lens is set at the top of a crane having a length of about 3 to 5 meters and shooting is performed by a camera operator who operates command units at the base of the crane (which may be referred to as crane shooting). There are other shooting situations in which a camera with a lens set in a natural field is operated from a distant place to shoot fierce animals or the like.
In such situations, the common cables for connecting the lens body and the command units are not sufficient in length, and extension cables for such particular purposes need to be prepared and set. Preparation and setting of such cables entails a cost and takes time.
In addition, use and setting of a plurality of long cables each including wires as many as about twenty for a plurality of command units of the same number involves the risk of breakage of the cable upon setting, which disadvantageously decreases reliability.
It has been demanded that the operation style with one television camera and a television lens can be changed according to the shooting situation by quickly switching between the tripod operation and the shoulder operation.
In the case of the tripod operation, the television camera and the television lens are integrally and quickly dismounted from the tripod.
However, the shoulder operation is not enabled unless the cables for connection with the zoom demand and the focus demand are disconnected from the television lens. This prevents quick changing of the operation style.
An object of the present invention is to provide a lens apparatus that can be easily set even in cases where the lens body and command units are distant from each other upon shooting without a decrease in the reliability.